Interaction Of Vegetation-soil System On The Reclaimed Land Of Coal Gob Piles In Lu'an Mining Area

The ecological restoration research of coal gob piles has always been a hot issue of Restoration Ecology at home and abroad.In this thesis,taking the vegetation-soil system on two reclaimed coal gob piles(Wangzhuang and Changcun coal gob piles,respectively)at Lu'an mining area in Shanxi as research object,and the selected 14 revegetation patterns and 2 natural restoration patterns(control),based on the plot sampling of plant and soil,the interaction relationship of vegetation-soil system were studied using the methods of quantitative ecology,soil biochemical analysis,high-throughput sequencing and principal component analysis(PCA),in order to reveal synergy mechanism between vegetation restoration and soil quality improvement,to screen the optimal vegetation restoration pattern and to provide a scientific basis for the future ecological restoration of coal gob piles.The main findings are as follows:(1)The succession of plant communities on the reclaimed coal gob piles in Lu'an mining area was in the early and middle stages,and the soil moisture and slope aspect were the main factors affecting the distribution of the plant communities.A total of 97 plant species were recorded in the reclaimedcoal gob piles in Lu'an mining area,belonging to 33 families of 91 genera,and the most common family was the Compositae(23 species),followed by Gramineae(18 species)and Leguminosae(11 species).The 48 quadrat sampleswere classified into nine vegetation communities(associations)by TWINSPAN classification,representing nine different types of plant communities(associations).The DCA ordination of 48 quadrats reflected the relationship between vegetation and environment on the reclaimed coal gob piles,indicating that the different plant patterns and slope aspectwere the main factors affecting the composition and distribution of plant association.The interspecific relationship among 13 dominant species showed that the dominant species in the plant associations had a positive correlation and the structure of plant associations was relatively stable,but the relationship between plant associations was weak.Thus,the succession of plant communities on the reclaimed coal gob piles was in the early and middle stages.(2)Vegetation restoration could effectively improvesoil physicochemical properties and enzyme activities on the reclaimed coal gob piles,but the improvement effect of different plant patterns was significantly difference.The results of soil physicochemical properties and enzyme activity showed that vegetation restoration could improve soil physical and chemical properties.Soil moisture was significantly affected by slope aspect.Pinus tabuliformis significantly improved soil physical and chemical propertiesonthe renclaimed coal gob piles of Changcun mine,and Pinus tabuliformis could improve soil fertility.The improvement of soil fertility promoted soil enzyme activity,which showed that the improvement of soil phosphorus could increase the soil alkaline phosphatase activity.Soil urease is significantly correlated with soil available nitrogen,and soil catalase had a significant relationship with plant association coverage.Different vegetation restoration patterns could increase soil enzyme activity at some degrees.(3)Significant differences in soil bacterial community composition and diversity under different vegetation restoration patterns on the reclaimed coal gob piles in Lu'an mining area.A total of 2179 OTUs were detected in soil bacterial community on the reclaimed coal gob piles of Changcun.At taxonomic level,Proteobacteria were the dominant populationof soil bacterial communities on the reclaimed coal gob piles of Changcun mine.As the most abundant nitrogen-fixing microbe,it provides a large number of nitrogen sources for vegetation-soil system.Compared with the control,vegetation restoration significantly increased the diversity of soil bacterial communities.The diversity of soil bacterial communities in the shady slope was higher than that of the sunny slope.(4)The ecological restoration quality of vegetation-soil system of different revegetation patterns on the the reclaimed coal gob piles in Lu'an mining area was differences.The results of correlation analysis showed that there was a significant positive correlation between plant species diversity and soil physical properties(p<0.05)and no significant correlation with soil chemical properties(p>0.05).It could be seen that vegetation has significant improvement effects on soil chemical properties,especially in the improvement of soil organic matter,total nitrogen and alkali nitrogen.It was also positively correlated with soil enzyme activity(p<0.05).The results ofprincipal component analysis showed that the ecological restoration quality of vegetation-soil system of different vegetation restoration patternson the reclaimed coal gob piles was different,and the restoration quality of vegetation-soil system on the reclaimed coal gob piles of Changcun mine was better than that of Wangzhuang mine.The pattern of Platycladus orientalis+Pinus tabuliformis-Festuca arundinacca+Medicago sativa has best restoration effect.In summary,vegetation restoration could significantly improve the species diversity of the plant communities,and then promote the soil physicalochemical properties and soil enzyme activity.Among them,the planted species of Pinus tabuliformis has obvious soil quality improvement effect,while theplanted species of Rhus Typhinahas poor has soil quality improvement effect.The pattern of Platycladus orientalis+Pinus tabuliformis-Festuca arundinacca+Medicago sativa is therefore recommended for future reclamation of abandoned coal gob piles in this and adjacent mining areas.